Best value for -XX:MaxPerSize for a 8GB Ram Laptop

Hi, 

I have several test suites in SoapUI Pro that includes groovy scripts, selenium webdriver stuff, loopsource etc. I started seeing the below error 

ERROR [errorlog] java.lang.OutOfMemoryError: PermGen space
java.lang.OutOfMemoryError: PermGen space

I have Windows 7 laptop with 8 GB of Ram. Currently I have the below setting in SoapUI.bat file

set JAVA_OPTS=%JAVA_OPTS% -Xms128m -Xmx4096m -XX:MaxPermSize=128m -Dsoapui.properties=soapui.properties

So I have two questions:

1- Should I make the -XX:MaxPermSize to 4096m as well considering I have 8 GB of Ram..??  

2- Also in soapUI-Pro-5.2.0.vmoptions fie, I have -Xms1000m. Do I need to change that and match it with what I have in my soapUI.bat file which is -Xms4096m??